Steam Generator and Washing Machine Having the Same

ABSTRACT

A steam generator having an improved structure to change water supplied into the steam generator into steam within a short period of time and a drum type washing machine having the same are disclosed. The washing machine includes a tub mounted in a cabinet, which constitutes the external appearance of the washing machine, for storing wash water, a drum rotatably mounted in the tub, and a steam generator mounted in the cabinet for supplying steam into the drum. The steam generator includes a case having a space for receiving a predetermined amount of water, the case being provided at one side thereof with an inlet port and an outlet port, a heater case disposed in the case such that the heater case communicates with the interior of the case, the heater case having an additional space, into which some of the water supplied into the case is introduced and a steam heater disposed in the heater case for heating the water introduced into the heater case so as to generate steam.

TECHNICAL FIELD

The present invention relates to a drum type washing machine, and moreparticularly, to a drum type washing machine having a steam generatorfor rapidly, supplying steam into a drum.

BACKGROUND ART

Generally, washing machines are classified into a pulsator type washingmachine, which performs a washing operation using water stream generatedby the rotation of a plate-shaped pulsator, and a drum type washingmachine, which performs a washing operation using falling of wash waterand laundry and a friction force between the wash water and the laundrygenerated in a horizontally disposed drum by the rotation of the drum.

The drum type washing machine has been increasingly used since the drumtype washing machine has advantages superior to the pulsator typewashing machine in that the amount of wash water and detergent usedduring the washing operation is small, damage to the laundry isminimized, and the laundry is minimally tangled.

The structure of a conventional drum type washing machine will bedescribed hereinafter with reference to FIG. 1.

As shown in FIG. 1, the conventional drum type washing machine includesa cabinet 10 constituting the external appearance of the drum typewashing machine, a cylindrical tub 20 horizontally supported in thecabinet for storing wash water, a drum 30 rotatably mounted in the tub20, the drum 30 being provided with through-holes, through which washwater and steam are introduced into the drum 30, a driving motor 40 fordriving the drum 30, and at least one steam generator 50 for supplyingsteam into the drum 30.

At the front part of the cabinet 10 is formed a laundry opening 13,which communicates with the interior of the drum 30 such that laundrycan be put into or removed from the drum 30 through the laundry opening13. A door 11 is hingedly mounted to the cabinet 10 adjacent to thelaundry opening 13 for opening and closing the laundry opening 13.

Along the inner circumference of the laundry opening 13 is mounted agasket (not shown) for preventing hot air from leaking through theconnection between the door 11 and the tub 20.

At one side of the drum type washing machine is provided a water supplyvalve 15, which is connected to an external water pipe (not shown) forsupplying wash water into the tub 20 or supplying water into the steamgenerator 50.

The steam generator 50 is connected with the water supply valve 15 suchthat the water supplied from the water supply valve 15 can be introducedinto the steam generator 50. The steam generator 50 heats the watersupplied from the water supply valve 15 to generate steam, and suppliesthe generated steam into the drum 30.

As shown in FIG. 2, the steam generator 50 includes a case 51constituting the external appearance of the steam generator, a waterlevel detecting sensor 60 for detecting the water level of watersupplied into the case 51, a heater 55 for heating the water suppliedinto the case 51, and a temperature detecting sensor 57 for detectingthe temperature of the heated water.

The case 51 is provided at one side thereof with an inlet port 103 (seeFIG. 1), which is connected to the water supply valve 15 (see FIG. 1)for allowing water to be introduced from the water supply valve 15through the inlet port 103. The case 51 is also provided at one sidethereof with an outlet port 105, through which steam generated in thecase 51 is discharged to the drum 30 side.

Also, the steam generator 50 is provided at one side thereof with asteam supply pipe 53 (see FIG. 1), which is a passage for guiding andinjecting the steam generated by the steam generator 50 into the drum 30through the outlet port 105.

However, the conventional drum type washing machine with theabove-stated construction has the following problem.

The amount of water supplied into the case 51 of the conventional steamgenerator 50 during the generation of steam is large, and therefore,time necessary to heat the water supplied into the case 51 into steam isincreased. Consequently, power consumption is increased.

DISCLOSURE OF INVENTION Technical Problem

An object of the present invention devised to solve the problem lies ona steam generator having an improved structure to change water suppliedinto the steam generator into steam within a short period of time and adrum type washing machine having the same.

Technical Solution

The object of the present invention can be achieved by providing a steamgenerator comprising: a case having a space for receiving apredetermined amount of water, the case being provided at one sidethereof with an inlet port and an outlet port; a beater case disposed inthe case such that the heater case communicates with the interior of thecase, the heater case having an additional space, into which some of thewater supplied into the case is introduced; and a steam heater disposedin the heater case for heating the water introduced into the heater caseso as to generate steam.

Preferably, the heater case is mounted in the case such that the heatercase is spaced apart from the bottom of the case.

Preferably, the heater case comprises: an introduction part having atleast one introduction hole, through which some of the water suppliedinto the case is introduced into the heater case; and a discharge parthaving at least one discharge hole, through which steam generated in theheater case is discharged.

Preferably, the introduction part is formed at the lower surface of theheater case.

Preferably, the discharge part is formed at the upper surface of theheater case.

Preferably, the at least one introduction hole has a diameter less thanthat of the at least one discharge hole.

The steam generator may further comprise: a temperature detecting sensordisposed in the case for detecting the temperature of the steamdischarged from the heater case.

The steam generator may further comprise: a water level detecting sensordisposed in the case for detecting the water level of the water receivedin the case.

In another aspect of the present invention, provided herein is a washingmachine including a tub mounted in a cabinet, which constitutes theexternal appearance of the washing machine, for storing wash water, adrum rotatably mounted in the tub, and a steam generator mounted in thecabinet for supplying steam into the drum, wherein the steam generatorcomprises: a case having a space for receiving a predetermined amount ofwater, the case being provided at one side thereof with an inlet portand an outlet port; a heater case disposed in the case such that theheater case communicates with the interior of the case, the heater casehaving an additional space, into which some of the water supplied intothe case is introduced; and a steam heater disposed in the heater casefor heating the water introduced into the heater case so as to generatesteam.

Preferably, the heater case is mounted in the case such that the heatercase is spaced apart from the bottom of the case.

Preferably, the heater case comprises: an introduction part having atleast one introduction hole, through which some of the water suppliedinto the case is introduced into the heater case; and a discharge parthaving at least one discharge hole, through which steam generated in theheater case is discharged.

Preferably, the introduction part is formed at the lower surface of theheater case.

Preferably, the discharge part is formed at the upper surface of theheater case.

Preferably, the at least one introduction hole has a diameter less thanthat of the at least one discharge hole.

The washing machine may further comprise: a temperature detecting sensordispose d in the case for detecting the temperature of the steamdischarged from the heater case.

The washing machine may further comprise: a water level detecting sensordisposed in the case for detecting the water level of the water receivedin the case.

Advantageous Effects

The steam generator with the above-stated construction has the followingeffects.

According to the present invention, the heater case, which isconstructed such that a predetermined amount of water can be introducedinto the heater case, is mounted in the case of the steam generator.Consequently, a small amount of water is instantaneously heated, andtherefore, time necessary to generate steam is reduced.

As the time necessary to generate steam is reduced power consumption isdecreased.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 is a perspective view schematically illustrating the structure ofa conventional drum type washing machine.

FIG. 2 is a schematic view illustrating the internal structure of aconventional steam generator.

FIG. 3 is a longitudinal sectional view illustrating the structure of adrum type washing machine according to an embodiment of the presentinvention.

FIGS. 4 and 5 are schematic views illustrating the internal structure ofa steam generator according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

FIG. 3 is a longitudinal sectional view illustrating the structure of adrum type washing machine according to an embodiment of the presentinvention, and FIGS. 4 and 5 are schematic views illustrating theinternal structure of a steam generator according to an embodiment ofthe present invention.

As shown in FIG. 3, the washing machine according to the presentinvention includes a machine case 110, a tub 120, a drum 130, a steamsupply unit, a temperature sensor 150, a circulating pump 160, acirculating channel 170, and a water level sensor (not shown) fordetecting the water level of the wash water in the tub 120. In thisembodiment, the washing machine is a drum type washing machine.

The machine case 110 constitutes the external appearance of the drumtype washing machine. At the front part of the machine case 110 isformed a laundry opening 111.

A door 140 is mounted to the machine case 110 adjacent to the laundryopening 111 for opening and closing the laundry opening 111. At theinner circumference of the laundry opening 111 is mounted a gasket 112,which accomplishes sealing between the door 140 and the laundry opening111.

Also, the machine case 110 is provided with a wash water supply pipe 113for supplying wash water into the tub 120. On the pipe line of the washwater supply pipe 113 is mounted a detergent box 114.

The tub 120 is mounted in the machine case 110 in a supported state.

To the bottom of the tub 120 is connected a drainage channel 121 fordraining wash water.

At the lower end of the tub 120 is mounted a wash water heater 122 forheating wash water supplied into the tub 120.

The drum 130 is rotatably mounted in the tub 120, and is disposed suchthat the open side of the drum 130 is directed to the laundry opening111 of the machine case 110.

At the circumference of the drum 130 are formed a plurality ofthrough-holes, through which wash water and steam supplied into the tub120 are introduced into the drum 130.

The steam supply unit is constructed to supply a predetermined amount ofsteam into the tub 120 and/or the drum 130. In this embodiment, at leastone steam supply unit is provided.

The circulating pump 160 is mounted on the drainage channel 121, whichis connected to the tub 120, and is operated to pump the wash watersupplied into the tub 120 such that the wash water can be circulated.

The circulating channel 170 is a pipe line which is connected to thecirculating pump 160 for guiding the circulating movement of the washwater pumped by the circulating pump 160.

Preferably, the end of the circulating channel 170, i.e., the wash waterdischarging side, extends through the gasket 112 such that the end ofthe circulating channel 170 is directed to the inside wall of the drum130. In this embodiment, the end of the circulating channel 170 isconnected to the steam supply pipe 220 as shown in the accompanieddrawings. Alternatively, the end of the circulating channel 170 may beconnected to the inside of the drum 130 without being connected to thesteam supply pipe 220.

The temperature sensor 150 is mounted at a predetermined position in thetub 120 for detecting the interior temperature of the tub 120.

The temperature detected by the temperature sensor 150 may be used tooperate the steam supply unit and to control the wash water heater 122.

Meanwhile, unexplained reference numeral 180 indicates a water supplyvalve assembly 180 for selectively supplying wash water introduced fromthe outside to the detergent box 114 or the steam supply unit, referencenumeral 181 indicates a wash water supply valve for controlling thesupply of wash water into the tub 120 through the detergent box 114, andreference numeral 182 indicates a water-for-steam supply valve forcontrolling the supply of water into the steam supply unit.

The steam supply unit is constructed to evaporate water, usinghigh-temperature hot air, into steam and to supply the steam into thetub 120 and/or the drum 130. The steam supply unit includes a steamgenerator (SG) 210 for generating high-temperature hot air to evaporatewater into steam, a steam supply pipe 220, through which steam generatedfrom the water evaporation by the steam generator 210 flows, and aninjection nozzle 230 for injecting the steam flowing through the steamsupply pipe 220 into the tub 120 and/or drum 130.

The injection nozzle 230 is constructed in the shape of a nozzle suchthat the steam can be smoothly injected through the nozzle. Preferably,the end of the injection nozzle 230, through which the steam isdischarged, extends through the gasket 112 such that the end of theinjection nozzle 230 is directed to the interior of the drum 130.

Hereinafter, the structure and the operation of the steam generator 210according to an embodiment of the present invention will be described inmore detail with reference to FIGS. 4 and 5. Arrows shown in FIG. 4indicate discharge of steam generated in a heater case, and arrows shownin FIG. 5 indicate introduction of water into the heater case.

According to the present invention, the steam generator 210 includes acase 211, a heater case 300, a steam heater 213, a steam sidetemperature sensor 214, and a water level sensor 215.

The case 211 may be constructed in the shape of a rectangular box, whichInstitutes the external appearance of the steam generator 210 and formsa steam generation space.

The case 211 is provided at one side thereof with an inlet port 103 (seeFIG. 1), which is connected to the water supply valve 182 for allowingwater to be introduced into the case 211 through the inlet port 103. Thecase 211 is provided at the other side thereof with an outlet port 105,which is connected to the steam supply pipe 220 for allowing steamgenerated in the case 211 to be supplied into the drum 130 through theoutlet port 105.

The heater case 300 is disposed in the case 211 such that the heatercase 300 communicates with the interior of the case 211. The heater case300 has an additional space, into which some of the water supplied intothe case 211 is introduced.

The heater case 300 serves to heat the water introduced from the case211 to generate steam and discharge the generated steam into the drum130 through the case 211.

Preferably, the heater case 300 is mounted in the case 211 such that theheater case 300 is spaced apart from the bottom of the case 211. Thisconstruction is necessary to form an introduction part, which will bedescribed below, at the bottom of the heater case 300.

Meanwhile, the steam heater 213 is mounted in the heater case 300. Thesteam heater 213 serves to heat water introduced into the heater case300, through the heat generation of the steam heater 213, into steam.

The steam heater 213 may be constructed using a sheath heater. Althoughnot shown in the drawings, a fuse is mounted in the steam heater 213 forinterrupting the supply of power when the steam generator 210 isoverheated so as to protect the steam generator 210.

Meanwhile, the heater case 300 comprises an upper case part 301 and alower case part 303.

Preferably, an introduction part having at least one introduction hole310, through which some of the water supplied into the case 211 isintroduced into the heater case 300, is formed at the bottom of thelower case 303 of the heater case 300.

Also preferably, a discharge part having at least one discharge hole330, through which the steam generated by the steam heater 213 in theheater case 300 is discharged, is formed at one side of the upper case301 of the heater case 300.

More preferably, the at least one discharge hole 330 is located at theupper surface of the upper case 301.

According to the present invention, it is preferable that the diameterD1 of the at least one introduction hole 310 be less than the diameterD2 of the at least one discharge hole 330.

In this case, the speed of the water introduced through the at least oneintroduction hole 310 is less than that of the steam discharged throughthe at least one discharge hole 330.

Meanwhile, the steam side temperature sensor 214 is disposed in the case211, and is electrically connected to a controller (not shown) of thewashing machine. The steam side temperature sensor 214 serves to detectthe interior temperature of the case 211 when the heat is generated fromthe steam heater 213.

Also, the water level sensor 215 is disposed in the case 211. The waterlevel sensor 215 includes three electrodes, i.e., a common electrode216, a long electrode 217, and a short electrode 218.

The water level sensor 215 serves to detect the water level of the watersupplied into the case 211. The water level sensor 215 is electricallyconnected to the controller (not shown) of the washing machine, whichcontrols all operations of the components of the washing machine,including the water supply valve assembly 180 and the steam heater 213.

The common electrode 216 and the long electrode 217 are formed such thatthe terminals of the common electrode 216 and the long electrode 217 areexposed approximately at the height set as the minimum water level ofthe water necessary to generate steam. The short electrode 218 isshorter than the common electrode 216 and the long electrode 217, and isformed such that the terminal of the short electrode 218 is exposedapproximately at the height set as the maximum water level of the waternecessary to generate steam.

Preferably, the height at which the terminals of the long electrode 217and the common electrode 216 are exposed is a height at which the steamheater 213 is fully submerged in the water.

Hereinafter, the operation and effects of the steam generator with theabove-stated construction will be described.

First, when electric power is supplied to the drum type washing machine,the controller (not shown) of the drum type washing machine controls thewater supply valve 181 of the water supply valve assembly 180 to supplywash water into the tub 120 to a predetermined water level, controls thecirculating pump 160 to circulate the wash water in the tub 120 to theupper part of the drum 130 along the outside of the tub 120, andcontrols the drum 130 to be rotated such that a laundry wetting processis carried out.

At this time, the controller controls the water-for-steam water supplyvalve 182 of the water supply valve assembly 180 to supply apredetermined amount of water into the case 211 of the steam generator210.

After the water is supplied into the case 211, the water level of thewater supplied into the case 211 is detected by the steam side waterlevel sensor 215, as previously described.

Meanwhile, some of the water supplied into the case 211 is introducedinto the heater case 300 through the introduction holes 310 formed atthe lower case 303 of the heater case 300.

At this time, the water introduced into the heater case 300 is heated bythe steam heater 213 such that the water is changed into steam.

Meanwhile, the interior pressure of the heater case 300 is higher thanthe pressure outside the heater case 300, i.e., the interior pressure ofthe case 211, due to the heat generated from the steam heater 213, andtherefore, the steam generated in the heater case 300 is discharged intothe case 211.

Since the interior pressure of the heater case 300 is higher than thatof the case 211 while the steam is generated in the heater case 300, andis then discharged from the heater case 300, no water is introduced intothe heater case 300 through the introduction holes 310.

Subsequently, the steam discharged into the case 211 is guided along thesteam supply pipe 220, which is connected to the case 211 and the drum130, and is then discharged into the drum 130, in which laundry isreceived such that the steam is directed to the laundry.

After the steam generated in the heater case 300 is discharged for apredetermined period of time, the water level of water in the heatercase 300 is lowered and the interior pressure of the heater case 300becomes lower than the pressure outside the heater case 300, i.e., theinterior pressure of the case 211.

At this time, the discharge of steam is interrupted and water isreintroduced into the heater case 300 through the introduction holes 310formed at the lower side of the heater case 300.

After a predetermined amount of water is introduced into the heater case300, the water is heated by the steam heater 213. As a result, theinterior temperature and the interior pressure of the heater case 300are increased, and therefore, steam is discharged again.

The steam generator 210 repeatedly performs the above-describedprocedure, whereby the steam is supplied into the drum 130.

While the laundry is wetted by the resupply of water into the tub 120,the rotation of the drum 130, and the operation of the circulating pump160, as described above, high-temperature steam is rapidly injected intothe drum 130 by the steam generator 210 according to the presentinvention, whereby the interior of the drum 130 is controlled to reach apredetermined temperature which can achieve the greatest washingefficiency of the washing machine.

The laundry wetting process and the steam supply process through thesteam generator 210 are carried out until the temperature detected bythe temperature sensor 150 reaches a target temperature.

When the temperature detected by the temperature sensor 150 reaches atarget temperature, the supply of steam through the steam generator 210is interrupted and the wash water supply valve 181 is controlled tosupply water into the tub 120 to the predetermined water level. Afterthat, the drum 130 is alternately rotated in the clockwise andcounterclockwise directions such that a post washing process is carriedout according to a predetermined program.

During the post washing process, the wash water heater 122 may be usedto heat the wash water in the tub 120 to a predetermined temperature, orthe circulating pump 160 may be operated by predetermined periods oftime to circulate the wash water.

After the post washing process is completed selected operations, such asa rinsing operation and a spin-drying operation, are successivelycarried out.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

INDUSTRIAL APPLICABILITY

According to the present invention, a small amount of water isinstantaneously heated in the heater case, which is disposed in the caseof the steam generator. As a result, time necessary to generate steam isreduced and therefore, power consumption resulting from the operation ofthe steam generator is decreased. Consequently, the present inventionhas considerably high industrial applicability.

1. A steam generator comprising: a case having a space for receiving a predetermined amount of water, the case being provided at one side thereof with an inlet port and an outlet port; a heater case disposed in the case such that the heater case communicates with the interior of the case, the heater case having an additional space, into which some of the water supplied into the case is introduced; and a steam heater disposed in the heater case for heating the water introduced into the heater case so as to generate steam.
 2. The steam generator according to claim 1, wherein the heater case is mounted in the case such that the heater case is spaced apart from the bottom of the case.
 3. The steam generator according to claim 1, wherein the heater case comprises: an introduction part having at least one introduction hole, through which some of the water supplied into the case is introduced into the heater case; and a discharge part having at least one discharge hole, through which steam generated in the heater case is discharged.
 4. The steam generator according to claim 3, wherein the introduction part is formed at the lower surface of the heater case.
 5. The steam generator according to claim 3, wherein the discharge part is formed at the upper surface of the heater case.
 6. The steam generator according to claim 3, wherein the at least one introduction hole has a diameter less than that of the at least one discharge hole.
 7. The steam generator according to claim 1, further comprising: a temperature detecting sensor disposed in the case for detecting the temperature of the steam discharged from the heater case.
 8. The steam generator according to claim 1, further comprising: a water level detecting sensor disposed in the case for detecting the water level of the water received in the case.
 9. A washing machine including a tub mounted in a cabinet, which constitutes the external appearance of the washing machine, for storing wash water, a drum rotatably mounted in the tub, and a steam generator mounted in the cabinet for supplying steam into the drum, wherein the steam generator comprises: a case having a space for receiving a predetermined amount of water, the case being provided at one side thereof with an inlet port and an outlet port; a heater case disposed in the case such that the heater case communicates with the interior of the case, the heater case having an additional space, into which some of the water supplied into the case is introduced; and a steam heater disposed in the heater case for heating the water introduced into the heater case to generate steam.
 10. The washing machine according to claim 9, wherein the heater case is mounted in the case such that the heater case is spaced apart from the bottom of the case.
 11. The washing machine according to claim 9, wherein the heater case comprises: an introduction part having at least one introduction hole, through which some of the water supplied into the case is introduced into the heater case; and a discharge part having at least one discharge hole, through which steam generated in the heater case is discharged.
 12. The washing machine according to claim 11, wherein the introduction part is formed at the lower surface of the heater case.
 13. The washing machine according to claim 11, wherein the discharge part is formed at the upper surface of the heater case.
 14. The washing machine according to claim 11, wherein the at least one introduction hole has a diameter less than that of the at least one discharge hole.
 15. The washing machine according to claim 9, further comprising: a temperature detecting sensor disposed in the case for detecting the temperature of the steam discharged from the heater case.
 16. The washing machine according to claim 9, further comprising: a water level detecting sensor disposed in the case for detecting the water level of the water received in the case. 